I am working on doing a short documentary with my XH A1 in a cave and wonder if anyone can give me some insights about lighting the stalactites, stalagmites and other formations.
I will be interviewing a speleologist and have the formations in the background. We won’t be in a very large cave, but the formations may be 20 to 30 feet behind the person being interviewed.
Due to the difficulty in reaching the specific cave we will be working in, I would prefer not having to lug a generator through the jungle and into the cave. Are there any portable lighting alternatives for this type of situation?
Thanks!
James

First and foremost, I'd contact the experts and see what kind of light sources they even ALLOW in the cave.

Many useful devices like lanterns or flares put off what might be fumes potentially toxic to the cave ecosystem.

One thing I'd consider is doing some experimentation with those Cayalume glow stick things.

A bunch of them placed behind a column plus a couple of strategically aimed LED "miner's helmet" direct lights might be all you need for a useful interview deep underground.

Heck, I'm probably dreaming here - but don't they make these in Red, Green, and Blue? I wonder what happens if you put a group of the three primary colors in a reflector of some kind. Wouldn't it be weird if you got a white-ish light out of that?

One of the points that we will be covering in the documentary is the need to respect the "leave no trace" philosophy when spelunking, so we really don't want to degrade the environment with our lighting while trying to teach proper enjoyment of nature's resources. The gentleman we will be interviewing is a proponent of low impact spelunking and will have to approve all the equipment we plan to use in the production. That's why I'm looking for alternatives for him to choose from.

When I mentioned using a generator, it would require hauling the machine through the jungle for about an hour and a half before reaching the cave entrance. Then we would have to extend cables for quite a distance into the cave to light the environment. I really don't want to do this.

What I was thinking about using are the 10 or 20 million candlelight rechargeable spotlights placed strategically throughout the cave. I can imagine using some gels to add color to the lighting. One of the problems I can foresee having is running out of juice 15 or 20 minutes into the production. Has anyone used this type of lighting before for dark environments?

I don't know if they would provide the amount of light you need, but they might be worth a look. They're really small and rugged, plus they run a long time on 4 AA batteries. Have been meaning to play around with them and my Z1 one of these nights. There's a review here: http://www.backpackgeartest.org/revi...y%20Kirschner/

Because of the way the LED is mounted and the reflectors, you won't get anything like a soft or even light however.

Well those Coleman LED lanterns cover a wide area. What I meant is that it's a point source of light, and you will see some shadows from the supports and plastic covering. It isn't a coverage issue but the rather harsh effect. Inside a cave I'm not so sure whether that would matter however.

I have 3 of the 500 LED lights from Flolights. http://www.prompterpeople.com/led500.php
They're very compact, comparable to the Lowel Caselight 2 fluorescents in output, but with a little bit more throw and a slightly more focused beam. The good part for you is that they are DC and can be run off cheap battery belts for a long time. Each one pulls only 40 watts of power, compared to 110 watts for the equivalent fluorescents. They're about the size of a small laptop computer, but a couple of inches thicker. They're 5600K, so you'd need to gel them with CTO if you want to mix them with tungsten.

However, if money's tight and you're looking for more DIY solutions, a combination of those Coleman type fluorescent lanterns, and the big flashlights you're talking about can work, if you diffuse the spotlights. You can also bounce them off reflectors, which I've done before. When you're in near total darkness, a little light goes a long way.

The type of effect that I was imagining for the documentary is similar to what Eric has posted. I was also thinking of possibly adding a gel or two too hyper amplify the effect of shadows crevices in dark corners.

I really like the idea and the portability of LED's, but I am afraid that with the non-stellar performance of the XH A1 in low light, I might not get the contrast I need. A complicating factor is that I really don't know how far the interviewee will be from the formations.

Does anybody know the color temperature of the Philips lamps used in many of the 10.000 and 20.000 candlelight spots on the market? I have written to distributors as well as to Philips, but have not been able to get an answer from them on color temperature.

Yes, they are predominantly 4100K but sometimes you can find a 6000K one which would be far more nice. 4100K would be okay though as long as that's all you use and don't try to mix with other color temperatures.

Yeah, it would be awesome. I've got a 400 watt inverter and a car...which contains a battery....it's not a deep cycle, so the first test I want to perform is if it will work with an inverter, since the one I have doesn't produce a pure sine wave. The next step would be to purchase a deep cycle battery(I already have a charger).
I need to try this out soon.
If this works out I bet you could buy a cave light setup for $1200 +- $100
If you want to do an interview in a cave I think a softlight would be very helpful also.

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